I am having the same issue. Got a new Phone today (Moto G) and cant install any Apps. Internet-Connection is up, factory-reset does not help. I use the same SIM as in my previous phone and (Browser-)Google seemingly doesn't know that I upgraded, yet. Although my new Phone is mentioned in the market (on the web), the "installed" and "install"-buttons still refer to my previous phone. Is that the same on your end?
–
OmphaloskopieFeb 11 '14 at 20:56

It's not the same, but the problem is definitely is. Maybe some temporary problem with Google Play for newly added phones.
–
xZeroFeb 11 '14 at 21:21

Won't work for the OP, as a factory-reset should already have done this :(
–
IzzyFeb 12 '14 at 0:11

it's all about the procedure!!! <br>It worked for me, have you try it?.... because i re-downloaded and reflashed my phone without success... but this process did work!!!
–
user53460Feb 12 '14 at 0:15

Why (and how) should I try it? I don't even have that problem. As to your steps: 2) a factory-reset clears data+cache, sure. 3) a f-r removes the account (user has to set it up after next boot). 4) is the only thing that could have triggered anything – so that might be something @xZero might wish to try.
–
IzzyFeb 12 '14 at 0:21

dude, if you dont have the problem just stand down... this is a validation problem regarding time format and handshankes. If you reset it you will be forced to go trough the wizard that will set up your phone and eventually will generate you this problem.
–
user53460Feb 12 '14 at 0:23

If only people having the problem are allowed to answer, we'd probably drown in unanswered questions. No more discussions here, and check what you "suggest" (and whom ;)
–
IzzyFeb 12 '14 at 0:26

Download .apk file of google play from here. If your device has the option, first select 'Uninstall updates' from your app manager for google play app. Then install this .apk file and then try using it. (You should also remove your google acc before uninstall/install).
Let me know if this worked!

Everything was going great with my brand new S5, until I turned on the Download Turbo.
Note, prior to turning on the booster, I was installing apps successfully over a WiFi connection.

I turned on Download Booster hoping to install apps from previous phone quicker.
Natural enough thing to do when you have 30 apps to get through, wouldn't you think?

All of a sudden I couldn't download anything from Google the Play Store.

Oddly, The Galaxystore (a wierd extra Play Store that comes with Galaxy Phones) worked, but most of my apps were not there, and those that were did not know I had purchased them.

After perusing the web, and resetting things and changing Google accounts, etc., I finally tried turning of my WiFi connection, and switching to only 4G mobile data.

Of course the S5's Download Booster was off now.

As if by magic, everything in Google Play Store started working again!

Okay, so maybe something in the Download Booster tries to make multiple connections to the Google Play Store server, and it doesn't like that.

So I turned off Download Booster, and turned on the WiFi, and turned off the 4G mobile data connection. Back to plain WiFi, as per the data connectivity configuration that was working in the beginning...

Alas, Google Play Store would not work again (same error), even with only WiFi on now.
Back to 4G, switch off WiFi, everything works on Google Play Store again. Consternation!

In summary:

If you have an S5 and you turn on the Samsung 4G + WiFi Booster and connect to Google Play Store, kiss your connectivity to Google Play Store via WiFi goodbye forever.
You can still connect with just 4G Mobile Data (as long as WiFi is off).

It's almost as if the Google Play Store server remembers indefinitely that you once tried to connect with WiFi and 4G together, and forbids your WiFi connectivity henceforth.

An error "403" is the response code of the server (access denied). So as t0mm13b wrote, it's an issue at Google's end. Nothing you could fix from your device. As the OP did a factory-reset (read the question again), there's no logic in your suggestion, sorry.
–
IzzyFeb 11 '14 at 22:28